Stroke, one of the acute cerebrovascular diseases, is the third leading cause of death in worldwide population and induces a highest disabling rate among various diseases. As indicated by the recent epidemiology references, the incidence of cerebrovascular diseases in China ranges from about 0.12% to 0.18%, which is the second cause among population death. There are 1.2 to 1.5 millions peoples newly developed cerebrovascular diseases each year, and 0.8 to 1 millions patients died, about 75% of survivals were disabled, and relapse rate within 5 years was up to 41%. The cerebrovascular diseases could severely affect the life quality of the elderly, bring an enormous burden to patients' family and the society. It also trends to increase in young population.
The cerebrovascular diseases are primarily classified into two types, hemorrhagic and ischemic, of which the latter is 60-70%, and is the most common type of cerebrovascular diseases. It is important to study the pathophysiological mechanism of ischemic cerebrovascular diseases and search for drugs which function as neuroprotection.
The research of the pathophysiologic mechanism of cerebral ischemia has been one of the most focuses of the neuroscience field since 1980s, and so far theories of cerebral ischemia concerning such as energy metabolism, acid intoxication, peroxidation injury, excitatory amino acid induced toxicity injury and calcium overload have been proposed, in which the last two play an important role in ischemic neuronal injury and death. According to pathophysiologic basis of ischemic cerebrovascular diseases, drugs currently used to clinically treat cerebral ischemia mainly comprise calcium ion antagonists (nimodipine), oxygen radical scavengers (VitE, SOD), neurotrophic factors (nerve growth factor, neurotrophic factor), excitatory amino acid antagonists, antioxidants and drugs which improve late-onset neuronal injury. These drugs function via various mechanisms of action, with uncertain therapeutical effects or less specificity or with the concomitancy of severe side-effects, and thus can not fulfill the clinical requirements yet. There are many commercially available drugs which can be used to improve cerebral circulation, metabolism and functions, such as piracetam, flunarizine, calan, ginkgo extracts. Although they all have certain characteristics, the treatment effects thereof on cerebrovascular diseases are uncertain. Research and development of novel drugs for treating ischemic cerebrovascular diseases is an important task in the field of pharmaceutics and pharmacology.
As used herein, “the extracts from rabbit skin inflamed by vaccinia virus” refers to the active substances extracted from the rabbit skin inflamed by vaccinia virus, as described in Chinese patent NO. ZL98103220.6, the entirety of which is incorporated herein by reference. Such extracts from rabbit skin inflamed by vaccinia virus are commercial available, with trade name of analgecine, which is manufactured by Vanworld Pharmaceutical (Rugao) Co. Ltd. The pharmacological effects of analgecine include: (1) analgesic effects, including obvious analgesic effects on hyperalgesia complexly induced by repeated cold stresses, which are achieved by activating the descending inhibition system of central nervous system; (2) effects on sense of coldness and abnormal perception: it has been showed by experiments in vivo and in vitro that such agent has the effects of changing the neuron sporadic activity of hypothalamus, suggesting that the agent has reparative and regulating effects on abnormal sense neuron sporadic activity, which is considered to be the cause for neuralgia and abnormal perception; (3) effects of improvement of peripheral blood circulation; (4) effects on regulation of autonomic nerves: it has been suggested by the experiment in vivo and in vitro that the agent can improve the symptoms of autonomic nerve system dysregulation by regulating the activity of central autonomic nerve; (5) effects on anti-allergic reaction: it has been suggested by animal experiments that the agent has effects on anti-allergic reaction type I, which has inhibitory effects on respiratory tract hypersecretion resulted from excitation of parasympathetic nerve, and also has inhibitory effects on up-regulating the density of nasal mucosa receptor M; (6) effects of sedation: it has been suggested by animal experiments that the agent has a sedative effect on the affective excitation state caused by various external stimulations.
Furthermore, the extracts from rabbit skin inflamed by vaccinia virus were discussed in the following applications: Chinese patent application NO. 99123485.5, filed on Nov. 12, 1999; Chinese patent application NO. 96123286.2, filed on Dec. 19, 1996; and Chinese patent application NO. 98103914.6, filed on Jan. 7, 1998.
However, the protective effects of analgecine on cerebral ischemia injury have not been reported yet. The present invention has investigated such effects, and found that analgecine has a beneficial effect on cerebral ischemia in the experimental animal models.